This invention relates to a diagnostic apparatus for analysis of varying states based on wave shape measurement, and particularly adapted for electrocardiographic and similar graphical analysis.
Electrocardiographic (EKG) analysis, for many years and even today, is based on the recording of EKG waveforms of a patient. Conventionally, a chart recorder includes a plurality of inputs which are adapted to be connected by appropriate leads to various appropriate positions on the patient. The recorder is then operated to record a plurality of different EKG signals. The chart recorder can be operated by suitably trained personnel to produce the series of the EKG charts. A trained cardiologist or specially trained physician can, by study of the EKG waveform charts, analyze the functioning of the patient's heart and determine the presence of any defective conditions.
As a result of past study and analysis, a series of rules applicable to the EKG charts have been developed which permit EKG-trained physicians to properly diagnose the presence of a wide range of heart diseases. The study of EKG charts therefore provides a basis for locating and anticipating abnormal heart conditions as well as subsequent monitoring of the condition of cardiac patients.
Although the chart recorder is a widely employed method of analysis, the requirement of skilled personnel to record the EKG signals and specialized medical personnel to analyze the charts results in a relatively expensive procedure. These features also limit the ready and convenient availability of the procedure.
With the development of computer and digital instruments, computer based diagnostic systems have been developed in which the EKG signals are digitized and stored in memory for computer processing. U.S. Pat. No. 3,698,386 for example suggests use of analog computer and refers to use of a digital computer which requires complex and expensive memory devices. The computer and memory may be on site or, more generally, is remotely located with the EKG signals transmitted over telephone lines or other suitable transmitting means. Analysis of the signals may be provided by various computer programs to produce an analysis similar to the diagnostic logic of the cardiologist. The computer based systems are also generally expensive and of limited availability.
Because of the complexity and costs associated with present devices, they are not therefore adapted to generalized use of clinical mass screening of individuals. As a result, electrocardiographic instruments and analysis are generally available only at hospitals, large medical clinics and the like.
There is, however, a need for a low cost instrument implementing existing clinical knowledge with can be employed without extensive technical training or skill, and therefore adapted for more widespread analysis of heart action and the like.
Many other areas of investigation employ similar analytical techniques in which correlation between recorded varying graphical display provides a basis for investigation of a varying state or condition. Thus, seismographic oil field analysis is based on waveform analysis. Generally, specialized and highly trained personnel are required to obtain the data and more important to analyze the recorded data. Thus, in such fields, improved low cost and reliable diagnostic instruments which can be operated with minimal skill personnel would be desirable.